#include <iostream>
#include<unistd.h>
#include<cstdio>
#include<cstring>
#include<sys/types.h>
#include<sys/wait.h>


void ChildWrite(int wfd)
{
    char c  = 0;
    int cnt =0;
    while(true)
    {
        write(wfd,&c,1);
        printf("child: %d\n",cnt++);
    }
}

void FatherRead(int rfd)
{
    char buffer[1024];
    while(true)
    {
        sleep(100);
        buffer[0]= 0;
        ssize_t n = read(rfd,buffer,sizeof(buffer - 1));
        if(n > 0)
        {
            buffer[n] = 0;
            std::cout<<"child say: "<<buffer<<std::endl;
        }
        else if(n == 0)
        {
            std::cout<<"n : "<<n<<std::endl;
            std::cout<<"child 退出，我也退出";
            break;
        }
        else
        {
            break;
        }
        break;
    }
}

int main()
{
    //1.创建管道
    int fds[2] = {0};//fds[0]:读端  fds[1]:写端
    int n = pipe(fds);
    if(n < 0)
    {
        std::cout<<"pipe error"<<std::endl;
        return 1;
    }
    std::cout<<"fds[0]: "<<fds[0]<<std::endl;
    std::cout<<"fds[1]: "<<fds[1]<<std::endl;

    //2.创建子进程
    pid_t id = fork();
    if(id == 0)
    {
        //child
        close(fds[0]);
        ChildWrite(fds[1]);
        close(fds[1]);
        exit(0);
    }

    close(fds[1]);
    FatherRead(fds[0]);
    close(fds[0]);

    int status = 0;
    int ret = waitpid(id,&status,0);//获取子进程的退出信息
    if(ret > 0)
    {
        printf("exit code: %d,exit singal: %d\n",(status>>8)&0xFF,status&0x7F);
        sleep(5);
    }
       return 0;
}

